gerald_clark:
The lines should be:etc/groupetc/gshadowetc/passwdetc/shadow

Note the absence of a leading "/".

Bootlocal.sh does not run until after extensions are loaded.Extension setup scripts should NOT start services.Instead they should install a startup script in /usr/local/etc/init.d.Modify bootlocal.sh to call this startup script.

Toshick:
As I understand, modprobe should be perform on extension load. When system boots up, vboxguest and vboxsf kernel modules should be loaded. But it can't be loaded because user/group is not exists on extension load stage. The question is how I should make user/group be available on extension load?Thanks.

gerald_clark:
modprobe in /opt/bootlocal.sh.

Another method would be to have the install script add the user to /etc/passwd et al.adduseraddgroup

Toshick:
It is interesting, but modprobe is not work for vbox modules. It said: Module not found. I use insmod insted in bootlocal.sh.

gerald_clark:
Did the extension do a depmod -a after creating the symlinks?